Posted
by
samzenpus
on Thursday December 27, 2012 @08:04AM
from the picking-over-the-pieces dept.

Lasrick writes "David Wright of the Union of Concerned Scientists and the Bulletin of the Atomic Scientists analyzes the debris from North Korea's December 11th Unha-3 launch. From the article: 'According to press reports, traces on the inner walls of the tank show that the first-stage oxidizer is a form of nitric acid called "red-fuming nitric acid," which is the standard oxidizer used in Scud-type missiles. There had been some speculation that this stage might instead use a more advanced fuel with nitrogen tetroxide (NTO) as the oxidizer. Since the Nodong engines believed to power the first stage are scaled-up Scud engines, the use of RNFA is not a surprise. There have also been claims that the stage uses a more advanced fuel called UDMH, but it appears instead to be the kerosene-based fuel used in Scuds. In his recent RAND study, Markus Schiller noted that a test Iraq performed using UDMH in a Scud engine gave poor performance, and that burning UDMH gives a transparent flame. The North Korean video of the launch instead shows an orange flame characteristic of Scud fuels (Figure 3 is an image from 12:44 into the video). These findings confirm that the stage is still Scud-level technology.'"

I was wondering whether the analysis was just based on video frames (since they talked about the colors of the flames and such) in the "AllThingsNuclear.org" article. The
article [allthingsnuclear.org] itself says that the analysis is based upon four pieces of the first stage of the Unha-3 rocket recovered by South Korea. The author of the article, David Wright [allthingsnuclear.org], surmises that all four pieces came from the first stage because they "were found in the same area"..
The four parts found were:
1 -- oxidizer tank (made of an aluminum-magnesium alloy) with a cool picture (fig 4) of the inside of the tank showing hoops and stringers supporting the wall
2 -- two bottles that make the "turbo pumps" to maintain pressure in the oxidizer tank as the fuel flow continues during launch
3 -- another part of the fuel tank (with the number "3" painted on the outside which is visible on the launch video)
4 -- what appears to be a support ring from the first stage body.
There's also a comment at the end about using "room temperature fuels" such as RFNA (red fuming nitric acid) allowing the use of a simplified design as compared to using cryogenic fuels which require a more complex design. Someone wrote in pointing out that RFNA is also used in the Russian
Kosmos 3M [wikipedia.org] space launch vehicle which is also derived from a ballistic missile. In fact, even the fins and the profile of the Kosmos looks like the fins on and the profile of the North Korean launch rocket. Pretty cool analysis, and I like that the author puts really links to the sources of the pictures he has in the article.

China wasn't really that interested in saving Kim Il Sung's hiney back in the '50's. China got involved in the Korean war because 1) they felt they needed a buffer zone between a US-sponsored South Korea and their borders, and, perhaps more to the point, 2) Mao Zedong didn't just hold grudges. He cherished them, and he was still nine kinds of annoyed at the US for backing Chiang Kai-shek during the Chinese Civil War. Yeah, Koreans fought during the Chinese Civil War, but Mao was never one to be grateful enough for someone to do something against his interest in thanks.